1. Field of the Invention
The present invention relates to the field of vehicle maintenance and repair. More specifically, the invention is directed to servicing transmission cooling systems.
2. Related Art
It is common for vehicles with automatic transmissions to have a cooling system for the transmission fluid in order to keep the operating temperature of the transmission within a desired range. Most cars, especially larger models, have such a transmission cooling system. Most trucks and vans require a larger transmission cooling system to handle extra stress placed on the transmission by, for example, carrying heavy loads or towing trailers. A typical transmission cooling system is connected to the transmission in such a way that transmission fluid is circulated from the transmission to a transmission fluid cooler through one line, then circulated through the transmission fluid cooler, and returned to the transmission through a second line.
A transmission cooling system can include, for example, a transmission fluid cooler inside the vehicle""s radiator, so that the transmission fluid cooler is immersed in the engine coolant inside the radiator. Thus, engine coolant, typically a combination of water and antifreeze, flows over the outside of the transmission fluid cooler while transmission fluid flows on the inside of the transmission fluid cooler. Heat is transferred from the transmission fluid circulating inside the transmission fluid cooler to the engine coolant circulating outside the transmission fluid cooler. Air flow over the outside of the radiator cools the engine coolant. Other cooling devices may also be used, for example, a device called a xe2x80x9cheat exchangerxe2x80x9d may be used in conjunction with or instead of the transmission fluid cooler described above. The transmission fluid cooler is also sometimes referred to as a transmission xe2x80x9coil cooler.xe2x80x9d A common design among all these devices is that each circulates fluid from the transmission through the device, in order to cool the fluid, and then returns the cooled fluid to the transmission. Thus, in a transmission cooling system, transmission fluid is circulated from the vehicle""s transmission system, through a transmission fluid cooler which controls the temperature of the transmission fluid, and returns to circulate through the transmission, thereby keeping the transmission within desired operating temperature range.
For various reasons such as extended use of the vehicle or transmission failure, the transmission fluid can become xe2x80x9cdirtyxe2x80x9d or contaminated with debris, for example, metal flakes from worn parts inside the transmission. Such debris can accumulate inside the transmission cooling system, in particular, inside the transmission cooler causing it to xe2x80x9cclogxe2x80x9d or become incapable of sufficient circulation of transmission fluid to provide adequate cooling. Occasionally, a transmission cooler becomes so clogged that it must be replaced. Transmission cooling system clogging can also lead to premature transmission failure. It is, therefore, crucial to clean the transmission cooling system as part of normal periodic transmission servicing. In addition, when a transmission is removed to be rebuilt or replaced with a new or rebuilt transmission, the transmission cooling system is typically cleaned to avoid contamination of the reinstalled transmission.
A number of conventional means are available for cleaning transmission cooling systems. One conventional means uses a pressurized container containing a liquid cleaner, for example, a can containing compressed solvent. Use of such means has many disadvantages. For example, the amount of cleaning that can be performed is limited by the amount of solvent and the can pressure, which may require the use and expense of extra cans. In addition, the cleaning liquid is only used once, which is wasteful because cleaning liquid is typically not completely dirty after only one use and can be used again. Disposing cleaning liquid which is capable of being reused is not only wasteful, but is also harmful to the environment.
Another disadvantage of using a compressed solvent can is that it does not provide a measure of the effectiveness of the cleaning. As a result, a transmission fluid cooler, which appears to have been cleaned may still be incapable of sufficient circulation of transmission fluid to provide adequate cooling, but may be reused and cause transmission overheating and damage.
Other conventional methods of cleaning transmission cooling systems may use air pressure. A source of such air pressure may be a pressurized system of air hoses commonly found in auto repair shops, typically referred to as xe2x80x9cshop air,xe2x80x9d typically at a pressure of 100.0 to 120.0 pounds per square inch (xe2x80x9cpsixe2x80x9d). Use of such methods is disadvantageous in that shop air may not be available at the location where the vehicle is to be serviced. Further, high air pressure can present safety concerns for the operators. In addition, shop air methods suffer from other disadvantages, such as using the cleaning liquid only once, which is wasteful because cleaning liquid is typically not completely dirty after only one use and can be used again. As stated above, such wastefulness is also harmful to the environment.
Accordingly, there is an intense need in the art for a new cooler flusher method and apparatus that can overcome the disadvantages and drawbacks in the conventional art; that can improve cost, efficiency, and safety; and that can remove environmental concerns.
In accordance with the purpose of the present invention as broadly described herein, there is provided method and apparatus for servicing a vehicle""s transmission cooling system.
In one aspect of the present invention, a service apparatus, for servicing a vehicle""s transmission cooling system, includes a source valve with inlet and outlet ports, a pump with inlet and outlet ports, and a return valve with inlet and outlet ports. The pump inlet is connected to the source valve outlet. The pump pumps fluid from the source valve inlet through the source valve outlet and the pump inlet to the pump outlet for servicing the transmission cooling system. The fluid returns from the return valve inlet to the return valve outlet and the pump then re-pumps the fluid into the transmission cooling system.
In another aspect, the service apparatus further includes a fluid source and a filter interposed between the fluid source and the source valve. In yet another aspect, the fluid returns to the fluid source prior to re-pumping the fluid. In one aspect, the service apparatus also includes a flowmeter interposed between the return valve and the fluid source and a filter interposed between the return valve and the flowmeter.
In one aspect of the present invention, the source valve inlet may also function as an air inlet. In yet another aspect, the source valve includes an air inlet and the return valve includes a waste outlet.
The service apparatus of the present invention can be used to perform a service method comprising the steps of pumping air into an inlet port of transmission cooling system to cause transmission fluid to flow out of an outlet port of the transmission cooling system; cycling a solvent through the transmission cooling system, where the solvent enters through the inlet port and exits through the outlet port of the transmission cooling system; re-cycling the solvent exiting through the output port through the transmission cooling system; and pumping air into the inlet port to cause the solvent in the transmission cooling system to exit through the outlet port.
These and other aspects of the present invention will become apparent with further reference to the drawings and specification, which follow.